1. Field of the Invention
The present invention relates to detecting devices for detecting malfunctions or marked abrasion of a bearing for a shaft.
2. Description of the Prior Art
One of the above-mentioned detecting devices is shown in Japanese Utility Model Second Provisional Publication 52-35379. In the device of the publication, a so-called "shaft vibration detecting piece" is radially movably arranged near a shaft which is rotatably held by a bearing. When, due to marked abrasion of the bearing, the shaft is subjected to abnormal vibration in radial direction, the shaft vibration detecting piece is shifted outward by the shaft to a position to actuate a limit switch. Thus, the marked abrasion of the bearing, which causes the abnormal rotation of the shaft, can be detected by the operation of the limit switch.
However, due to its inherent construction, the above-mentioned conventional detecting device has the following drawback.
That is, the conventional device can not detect an abnormal abrasion of the bearing which causes axial vibration of the shaft. In fact, even when the axial vibration of the shaft occurs due to peeling of parts of the bearing or the like, the shaft vibration detecting piece is not moved by the shaft. In this case, there is a possibility that the severely worn bearing is used until the same is completely broken. Of course, this is a serious matter because pieces in the broken bearing tend to induce trouble of a system in which the bearing is employed.